A production process has been defined as part of an industrial equipment manufacturing project. The process is intended to produce steel bolts with a length of 20 cm. The control limits are 19.955cm and 20.045cm.The measurements made at the end of the process yielded the following results:

A The process is under control. It should not be adjusted.B A special cause should be investigated, the process should be adjusted.C The control limits should be adjusted.D The measuring equipment should be recalibrated.

The question is from Oliver - and the answer is option B but why ? all the range above is between the control limit then answer should be "A"pls somone help here.